HYMENOPTERA — MELLIFERA. 961 
ordinary brushes, or, as we may term them, brushlets in all male bees, 
and in the females of the parasitic species, only enable the insects to 
clear themselves from the pollen with which the body has been 
powdered in the flowers which they have been plundering: in the 
females of the working bees, however, they serve to collect the pollen 
to certain parts of the body more thickly clothed with hairs, and 
which are the real pollen brushes. In the social bees these are 
placed (in addition to the external pollen plate) on the inside of the 
posterior tibize and tarsi (fig. 92. 20.). In other working bees, Eu- 
cera, Systropha, Anthophora, Xylocopa, &c., the pollen brush is 
placed on the outside of the two posterior tibia and tarsi (fig. 91. 8.) ; 
whilst in others (Anthidium, Osmia, Megachile, &c.) the under side 
of the abdomen is entirely covered by it (fig. 91. 14.). 
From these considerations, M. St. Fargeau is induced to propose the 
division of each of the two families of the Mellifera into two groups, 
under the names of “ parasites” and “ récoltantes,” subdividing the 
latter into various minor divisions from the situation of the pollen 
plates and brushes. M. Latreille, however, has not adopted this mode 
of arrangement. Indeed it is to be observed that the variation in the 
structure of the species, thus varying in their habits, does not seem to 
warrant the establishment of them into separate families. This cir- 
cumstance appears naturally dependent upon two considerations: 1st, 
it is essential that the parasite in its perfect state should possess a 
certain resemblance to the animal in the nest of which it deposits its 
eggs, so as to deceive the latter and its associates*; and 2nd, the 
nature of the food of both being similar, the variation in structure 
is much less striking than if the parasite were carnivorous, as the 
Ichneumonide, and the animal attacked (as the caterpillars of Le- 
pidoptera, &c.) herbivorous. The parasitic connexion indeed goes 
no further than this, viz. that the larva of the parasite eats up the 
food of its fosterer, and so starves it to death ; the larve of both are 
therefore pollinivorous, and the differences which will naturally be 
most striking, will consequently be found in those organs which are 
* So closely is this resemblance carried in the parasitic Bombi, that the propriety 
of their generic separation from the working humble bees has even been questioned. 
In like manner, the Dipterous genus Volucella, which is parasitic upon bees, so 
closely resembles them in general appearance, that it requires some little entomo- 
logical skill to distinguish them from the humble bees: other instances to the same 
effect might be adduced. 
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